<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>验证设置width=2000px的效果</title>
  <style>
    .flex-wrapper {
      display: flex;
    }
    .item {
      width: 2000px;
      height: 200px;
      background: #ccc;
      border: 1px solid #000;
      margin-bottom: 20px;
    }
  </style>
</head>
<body>
  <div class="item">display: block</div>
  
  <div class="flex-wrapper">
    <div class="item">display: flex</div>
  </div>
</body>
</html>